The Specific Phase: Where Ultra Trail Runners Build Performance
Many trail runners enjoy the base phase.
Fewer truly understand what comes next.
Because this is where training starts to feel harder — and more meaningful.
At Arduua, we call it:
👉 Build Performance
This is the phase where your training begins to reflect the real demands of trail running — physically, mentally, and technically.
From Base to Specific — What Changes?
In our previous post on base training, we focused on building:
- Aerobic capacity
- Structural strength
- Mobility and durability
- Volume tolerance
Now, we use that foundation.
The Specific Phase is not about starting from zero —
it’s about applying everything you’ve built under more demanding, trail-specific conditions.
Training Phases Through the Year (Big Picture)
1️⃣ Base Phase – Build the body
2️⃣ Specific Phase – Build performance
3️⃣ Pre-Competitive Phase – Build race readiness
4️⃣ Taper & Competition – Peak
5️⃣ Transition Phase – Recover & reset
This article focuses on Phase 2 — where performance is developed.
🎯 Primary Goals of the Specific Phase
According to Arduua coaching methodology, this phase is designed to:
- Improve aerobic and anaerobic thresholds
- Introduce VO₂max training in a controlled, progressive way
- Increase specific muscular strength for trails
- Adapt the body to race-like demands
- Develop power, efficiency, and fatigue resistance
In simple terms:
👉 You move from building capacity → to using capacity.
What Makes This Phase Different?
1. Intensity Is Introduced — Carefully
During the base phase, intensity is limited.
Now we introduce structured intensity sessions such as:
- VO₂max intervals
- Threshold sessions
- Tempo training
At Arduua, intensity is applied in a smart rotation:
- Every 3rd week → VO₂max
- Every 3rd week → Threshold
- Every 3rd week → Tempo
This ensures progression without overload and keeps you consistent.
2. Training Becomes Terrain-Specific
Trail running is not flat — so your training shouldn’t be either.
We introduce:
- Uphill power sessions
- Downhill conditioning
- Technical terrain running
Why this matters:
- Uphill builds strength and endurance
- Downhill builds durability and control
- Technical terrain improves efficiency and confidence
Professional coaches like Jason Koop emphasize:
👉 Specificity drives performance.
The closer your training reflects your race terrain — the better prepared you’ll be.
3. Strength Evolves Into Performance Strength
Strength training now becomes heavier and more specific.
We introduce:
- Squats
- Deadlifts
- Hip thrusts
This develops:
- Power for climbing
- Stability under fatigue
- Injury resistance on descents
Strength is no longer just supportive — it becomes a key part of performance.
Once a strength base is established, we convert it into power.
We introduce:
- Jump squats
- Box jumps
- Bounding
- Single-leg hops
These improve:
- Explosive uphill running
- Running economy
- Reactivity on uneven terrain
Strength must be translated into movement-specific power.
👉 Quality over quantity.
5. Long Runs Become More Specific
You’re no longer just accumulating time.
Now long runs include:
- Elevation
- Terrain variation
- Fatigue resistance
- Structured efforts
👉 You train your body to perform when it matters most — when tired.
Example Week — Specific Phase
Here’s how a typical week can look:
Monday – Recovery + Core
- 60 min easy run, hike, or cross-training
- 30 min core strength
Tuesday – Fartlek Session (~70 min)
- Warm-up
- 4 min hard
- 10 min moderate
- 2 min hard
- Cooldown
🎯 Focus: Threshold development
Wednesday – Strength Day
- 15 min mobility work
- 30–45 min strength training (lower body focus)
Thursday – Aerobic Progression (~60 min)
- Easy → steady → moderate effort progression
- Optional upper body strength (for pole usage if relevant)
Friday – Rest
Saturday – Long Trail Session (~2–3 hours)
- Easy trail running
- Finish with uphill intervals
Sunday – Easy Trail (~2 hours)
- Run or hike
- Focus on elevation and time on feet
- Keep effort low
👉 Balance stress, recovery, and specificity throughout the week
What Professional Coaches Agree On
Across endurance coaching, there is strong alignment:
- Intensity must be controlled
- Training must be specific
- Strength and power are essential
- Recovery drives adaptation
At Arduua, we combine these principles into a structured system tailored specifically for trail runners.
Common Mistakes in the Specific Phase
❌ Too much intensity
❌ Not enough recovery
❌ Skipping strength and plyometrics
❌ Ignoring terrain
❌ Training hard every week
The result?
- Injury
- Plateau
- Burnout
How This Phase Fits Into Your Season
The Specific Phase typically lasts around 8 weeks and prepares you for:
➡️ Pre-competitive training
➡️ Race-specific intensity
➡️ Terrain and race demands
If the base phase built your engine —
this phase teaches you how to use it.
Final Thoughts
The Specific Phase is where performance is built.
Not by doing more —
but by doing the right work at the right time.
Stay consistent.
Stay patient.
Train with purpose.
How We Apply This at Arduua
The principles described above are not theory — they are the foundation of how we coach athletes across the entire season.
At Arduua, base training is integrated into a structured yearly methodology that combines aerobic development, strength, mobility, technique and data-driven load management. Each phase of training builds logically on the previous one, ensuring athletes develop not just fitness, but durability, resilience and long-term performance capacity.
If you want to understand how this base phase fits into our full training system — from onboarding and testing to race-specific preparation — you can read more here:
Choosing the Right Level of Support
If you want:
- A fully individualized base built around your history, terrain & goals → Personal Coaching
- Structured base plans selected and timed for your season → Membership Plans
- A ready-made base plan to start building consistency → Training Plans
Train · Race · Belong
The base phase built your body.
Now you build performance.
You’re not just preparing for a race —
you’re becoming a stronger, more complete trail runner.
/Katinka Nyberg, Arduua Founder, katinka.nyberg@arduua.com